Bug#1078751: steam-devices: Add Appstream metainfo announcing HW support

[Simon McVittie]

On Thu, 22 Aug 2024 at 17:26:29 +0200, Petter Reinholdtsen wrote:
> [Petter Reinholdtsen]
> > My edition of /usr/share/misc/usb.ids do not list this ID:
> 
> Sorry, my eyes are obviously blind:
> 
> >         0202  Rocket Launcher
> 
> As far as I can tell, this is the device supported by pymissile, which I
> doubt is supported by steam.  Not quite sure where things went wrong
> here.  I suspect a cut-n-paste error on my part somewhere.

I see you've committed "Converted steam-devices AppStream info to
upstreamable patch." to the steam-installer git repo. I'm going to
revert this because, just like the current metainfo (#1079356), it
seems incorrect: Steam does not actually have any support for 1130:0202,
a desk toy that fires small plastic missiles under USB control.

steam-devices' main function is to relax the default access control on raw
HID device nodes for several game controller types (various generations of
Steam Controller, Xbox, Playstation and Nintendo controllers, plus their
more common third-party clones), in ways that are a security reduction
on multi-user systems, but are necessary if you want to pass through raw
HID access to Proton, Steam Input or similar frameworks. It's packaged
separately because it's also useful for some non-Steam components like
sc-controller[1] or maybe Wine, but it's a security vs. functionality
trade-off, which as we've discussed previously, does not seem appropriate
to install automatically just because you plugged in a particular game
controller.

As Free Software advocates, I also think it would be inappropriate for
us to install Steam itself just because the user happens to plug in a
game controller while having non-free enabled. Obviously I wouldn't be
maintaining steam-installer if I didn't value the ability to install
Steam easily, but the decision to install it should be a decision,
not something that happens by mistake.

So I don't think it would be appropriate to add metainfo that says
either Steam or steam-devices <provides> those game controllers' device
IDs. The relevant device drivers variously live in the kernel (for
typical use-cases), or in SDL (for some optional lower-level access),
or in the proprietary part of Steam (for Steam Input's ability to make
a game controller emulate an Xbox 360 controller, a keyboard and/or a
mouse for compatibility with games that only support one of those).

If it would be useful for Steam to declare <supports> on particular
device IDs, we can discuss that, and I think that would likely be much
more appropriate than <provides>. But I don't think simply copying every
vendor/product pair from the udev rules would really be practically
useful, and I don't want to spend my limited upstream influence on trying
to upstream things that I cannot, personally, justify to them.

Thanks,
    smcv

[1] https://github.com/kozec/sc-controller, not currently in Debian